From the Mayor's Office of Emergency Preparedness: Due to the I-85/Piedmont response effort, the City of Atlanta will have a delayed opening
time of 10 a.m. If you have questions, please call 404-546-0311 between the hours of 7 a.m. and 6 p.m. Residents are encouraged to utilize MARTA and
other commute options for travel within the city. We will share more details as they become available. Please allow additional travel times in the
city as delays are expected.

Steel/concrete: concrete is very susceptible to prolonged high heat. It will weaken tremendously, and actually turn to powder. Steel has a very high
melting point, as previously mentioned, but it also tends to lose a lot of its strength when heated to below that melting point. Most steel/concrete
structures are designed using composite design, which means the abilities of both materials together are used instead of one or the other.
Steel/concrete are pretty symbiotic in that respect... you get the inflexibility of concrete combined with the strength of steel. If either begins to
fail, the whole structure will quickly fail.

PVC/CPVC: both plastics are similar; polyvinyl chloride (PVC) essentially has a lower melting point than chlorinated polyvinyl chloride (CPVC).
Neither is especially flammable with heat, but both will burn intensely if ignited by a flame. Since they contain chlorine, both will put off fumes
containing chloride compounds... and almost all chemical compounds containing large proportions of chlorine are hazardous. Think hydrochloric acid
(HCl), bleach, chloroform, and chlorine gas (a major ingredient of mustard gas).

Bottom line: the heat needed to collapse the bridge that way had to be extreme and prolonged. CPVC, as reported, can provide such heat. But CPVC (as
with almost any plastic) would not spontaneously combust. There had to have been an ignition flame, and it would have to have been substantially more
than just a spark. Also, if this was caused by burning PVC/CPVC, the fumes would be highly toxic, although not overly persistent. The magnitude and
appearance of the smoke, in my experience, is consistent with burning PVC/CPVC, although it is also consistent with many other types of
combustibles.

originally posted by: TheRedneck
This is going to be a serious mess. I-85 is a major, major artery.

I wanted to throw a little technical data in...

Steel/concrete: concrete is very susceptible to prolonged high heat. It will weaken tremendously, and actually turn to powder. Steel has a very high
melting point, as previously mentioned, but it also tends to lose a lot of its strength when heated to below that melting point. Most steel/concrete
structures are designed using composite design, which means the abilities of both materials together are used instead of one or the other.
Steel/concrete are pretty symbiotic in that respect... you get the inflexibility of concrete combined with the strength of steel. If either begins to
fail, the whole structure will quickly fail.

PVC/CPVC: both plastics are similar; polyvinyl chloride (PVC) essentially has a lower melting point than chlorinated polyvinyl chloride (CPVC).
Neither is especially flammable with heat, but both will burn intensely if ignited by a flame. Since they contain chlorine, both will put off fumes
containing chloride compounds... and almost all chemical compounds containing large proportions of chlorine are hazardous. Think hydrochloric acid
(HCl), bleach, chloroform, and chlorine gas (a major ingredient of mustard gas).

Bottom line: the heat needed to collapse the bridge that way had to be extreme and prolonged. CPVC, as reported, can provide such heat. But CPVC (as
with almost any plastic) would not spontaneously combust. There had to have been an ignition flame, and it would have to have been substantially more
than just a spark. Also, if this was caused by burning PVC/CPVC, the fumes would be highly toxic, although not overly persistent. The magnitude and
appearance of the smoke, in my experience, is consistent with burning PVC/CPVC, although it is also consistent with many other types of
combustibles.

TheRedneck

Well then....that was a refreshingly insightful post.

It has my mind wandering a bit more into conspiracy now.

I wonder how long those spools of pipe were under that bridge. Was this a planned act of arson by someone that knew what you just posted? If so, was
it planned by the City to cause an incident in order for something else to happen or project to be postponed because of some budget mishap? Or was it
simply city employee that was part of the crew that put these spools there, had the knowledge you have, happens to be an arsonist and decided to wreak
havoc on the City in a manner that will literally cripple travel here for a while?

Forgot to tell you...GREAT SHOT! That may be the best shot I've seen of the fire.

It had to be a terrorist attack. (Sarcasm) Using 9/11 conspiracy logic, the black smoke means the fire is oxygen starved. Oxygen starved means the
fire was not hot enough to cause collapse... more sarcasm.

I do hope nobody gets hurt, and they can get the road way fixed as quick as possible.

The type of foam being used would probably be suggestive of the type of fire being dealt with. It is unlikely that the fire would have been fought
with foam, unless some sort of flammable liquid were involved though, so its probably best to start with the tentative assumption, that the fire
involved a liquid fuel of some sort, or that the material being burned created potentially flammable/explosive gasses.

The report said that some utility conduit or something, was laid out under the overpass, for use in some sort of construction. It is possible that
these reels of plastic tubing being burned, created a flammable vapour, which necessitated the use of a foam retardant, but more data would be
required to confirm that.

In any case, I would have thought that if terrorism was a possibility here, the first media organisation to jump on that, would have been the
permanently rabid assortment of filth that is the Fox News organisation. Since they make no such suggestion in the linked article, I wonder where the
idea sprung from?

Why? Something similar happened to Route 78 in New Jersey almost 30 years ago. A bunch of old tires were stored under an overpass near Liberty
Airport and they caught fire and buckled several of the steel beams in the outer roadway.

Confirmed damage to the South bound section of I-85 as well. So, both directions of 85, through the heart of Atlanta closed, indefinitely.

Crews are still putting out hot-spots at the scene. There is gridlock all over the city. 400 South bound closed, being diverted at Sidney
Marcus. Buford-Spring Connector closed due to too much volume as people desperately try to come up with a plan B to get around.

originally posted by: proteus33
a reply to: kosmicjack
bridges don't just burst into flame. and how many electrical wires have to be bundled there to generate that much fire.

It was supposedly a "secure" storage area for construction materials, under the interstate. So, if it is an accident, some jackass made the
call to store highly-flammable materials under a bridge in a major American city listed as having some of the worst traffic in the world.

I work in Buckhead but luckily I come in from 75 and West Paces. I'm sure traffic will be a nightmare locally for months and I'm sure that 75/285
will pick up a lot of the slack. 85 south to 285 west to 75 south to the connector heading south and vice-versa heading north. The new stadium will
only make matters worse...

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